Genetic aspects of the demography of Brazilian Terena Indians

HLA Antigens in South American Indians

“…However, the Brasilian tribes have been only minimally exposed to infectious diseases introduced in post-Columbian times, except malaria (Black et al 1974). Furthermore, it now seems that other polymorphisms are reduced, there being characteristically only 0 of the ABO, reduced Rh and Gm diversity and no variation in Albumin, Hemoglobin or many enzymes (Salzano 1972). The absence of whole cross-reactive groups of HLA antigens wouId require that the selective pressure operated across these groups.…”

Mortality patterns in Cuanalan, Mexico: 1866–1970

“…There has been a gradual decline in the proportion, and the lowest frequency occurs in the most recent time unit , with a reduction of almost 17 per cent from the sample of deaths for 1866-90. Nevertheless, nearly 60 per cent of all sampled deaths since 1866 are children who failed to achieve reproductive maturity, and this figure is higher than in ten of the twelve modem Latin American populations cited by Salzano (1972 of infants has historically been well under six months. The consistently high mortality within the first month of life is further evidence that the time of infant death has not been randomly distributed throughout the first year.…”

“…Generally, agricultural populations are marked by the highest indices for the opportunity of selection (Salzano, 1972). A number of workers subscribe to the theory that infectious diseases have formed the primary selective "pressure" in recent human evolution (Haidane, 19S7;Motulsky, 1960;Blumberg, 1970;CavalliSforza and Bodmer, 1971, p. 321).…”

The Semsa: A bio-demographic study

“…On the basis of demographic structure with patterns of subsistence, ecological adoption and social organisation, Salzano (1972) and Perez Dier and Salzano (1978), in order to classify the American Indian tribes, have suggested that there are three stages of evolution; "Stage A would be represented by hunters and gatherers with incipient agriculture; Stage B by more advanced agriculturists and fishers; and Stage C by pastoralists and populations living in densely inhabited areas as well as industrialized centres". Taking this classification into consideration it seems that the Semsa as a community belong to the Stage B since they are mainly agriculturists and relatively isolated.…”